CRISPR Scientists

Early research that opened the door to the CRISPR genome engineering tool occurred in 1987, when Japanese scientists studying E. coli bacteria encountered unusual repeating sequences in the DNA of the organism, but did not know what they did. Over the next few decades, researchers such as Francisco Mojica and Ruud Jansen found unusual repeating sequences in bacteria and archaea and hypothesized that the sequences functioned as an adaptive immune system. They named these sequences Clustered Regularly Interspaced Short Palindromic Repeats (hence the acronym CRISPR). In 2007, two food scientists (Philippe Horvath and Danisco France) conducted research that proved that CRISPR systems were an adaptive immune system. They discovered that when a bacteria is attacked by a virus and its enzymes repel the attack, new enzymes come along and collect the remains of the virus’s genetic code and store these fragments in the CRISPR spaces. When another virus attacks the bacteria, the bacteria produces special attack enzymes (known as Cas9 enzymes) to attack the virus. If the virus matches that of a previous attacker, the Cas9 enzyme starts to destroy the virus’s DNA to repel the attack. Clustered Regularly Interspaced Short Palindromic Repeats are the hallmarks of a bacterial defense system that forms the basis for CRISPR-Cas9 genome editing technology.

In 2012, biochemists Jennifer Doudna and Emmanuelle Charpentier developed a method of repurposing CRISPR to cut DNA with a type of genetic scissors in precise locations or order to edit or remove genes that created disease-causing mutations or other effects. For their work, they received the 2020 Nobel Prize in Chemistry. “The CRISPR/Cas9 gene scissors can lead to new scientific discoveries, better crops, and new weapons in the fight against cancer and genetic diseases,” according to the Nobel Prize Web site. Other scientists—including Luciano Marraffini, Virginijus Šikšnys, Dana Carroll, and Feng Zhang—also played a major role in developing CRISPR as a gene-editing tool.

While the use of CRISPR offers great promise, it has also created ethical concerns about the use of human genome editing for reproductive purposes. Despite these concerns, He Jiankui, a Chinese biophysicist, announced in November 2018 that twin girls had been born from embryos that he and his colleagues had edited using CRISPR. This news prompted a major backlash from the scientific world and medical ethicists. In 2019, a Chinese court sentenced He Jiankui to three years in prison for “illegal medical practice.” The debate about the appropriate use of CRISPR and other gene-editing technologies will continue because they have the potential to make significant changes to the genomes of humans, animals, and plants.